Device for generation of high pressure



Feb. 12, 1952 J, MORAVEC 2,585,818

DEVICE FOR GENERATION OF HIGH-PRESSURE Filed Feb. 21, 1948 /4 IN VENTOR.

Fatented Feb. 12, 1952 DEVICE FOR GENERATION OF HIGH PRESSURE JosefMoravec, Mala ChuchlefCzechoslovakia Application February 21, 1948,Serial No. 10,165 In Czechoslovakia September 23,, 1946 Section 1,Public Law 690, August 8, 1946v Patent expires September 23, 1966 14Claims.

The present invention relates to a method and a device for generation ofhigh pressures by making use of the dilatability of different materialsby action of heat.

The dilatation of solid materials due tothe effect of heat generatespressures, the magnitude of which is dependent upon the specific heatand weight of the substance and upon its coefiicient of volumedilatability. The equation in which the respective values have been putup shows that different substances, subjected to the action of heat,produce different pressures.

According to the present. invention the dilatability of the substancesis utilized in the following way. In a closed space, filled up by anysubstance whatever this substance is heated in a suitable manner (e. g.by electricity) up to a certain temperature at which the substanceshould attain the maximum of dilatation. The substance, being in aclosed space, cannot dilatate, on the contrary, it must compress,itself, whereby it is deforming internally, or changing its structureand modification. It is of course necessary to arrange the closed spacefor a compressed substance in a device of suitable dimensions to enablethe device to support high pres.- sures, generated by dilatation of theheated substance. After cooling the compressed substance remainsdeformed, if the internal pressures, generated by the dilatation, werehigher than. the elasticity limit of the compressed substance. anothercase the closed end of the space is not entirely filled up by the heatedsubstance, the remaining space being filled up by another substancewhich shall be subjected to the pressure. If the first substance isheated, it dilatates and compresses the tested substance which owing tothe action of the pressure of the first substance is deformed andreduces its volume. The com pression makes it warm and after cooling itkeeps its reduced volume together with its changed structure, or itschanged modification.

Examples of a device for generating high pressures are illustrated inthe accompanying drawings, where Fig. 1 shows the device in alongitudinal section,

Fig. 2 showing another device of this kind, equally in longitudinalsection of the right hand extremity, the left hand extremity, a sectionof which is shown on the Fig. 3, being arranged symmetrically, withexception of some minimal differences which will be described later.

In comparison todevices for generating high pressures used hitherto, e.g. presses, the inven- 2 tion ofiers the advantage of obtaining muchhigher pressures by means of smaller and less expensive devices.

The arrangement shown in the Fig; 1 consists in principle of a. body I,in which is lodged a hollow cylinder? of thick walls and a small innerwidth, preferably with a low coefficient of warm dilatability, e. g.made of glass, porcelain, corundum and the like. The central bore ofthe. cylxinder 2 passes on the left side into a conical recess, acorresponding conical projection. 3; of a metallic coveri engagingtherecess, thecover l'f" being insulated against the body Iby awasherand tightened to. the same by circumferential screws 3', insulatedagainstthecover l by washers It and by intermediate layer It.Theiopening in the cylinder 2v continues on theright hand even in thebody I, being closed therein by a closing cone 4', screwed into thebody. I. Into the bore of the cylinder 2 there is lodged a metaliic bar5, heated by electrical current, supplied from the line of the closingcone 3 and that of the body I (the supply lines are not shown). Thesection and the length of the bar 5 have to be of convenient dimensionsin order to obtain a sufiicient elongation of the bar heated. Theremaining space of the cavity of the body I is filled up by the testedmaterial 6- and' the cavity is closedby the cone 4'; The cone Send thebody I are brought into contact with" an electric supply line, theheated metallic bar dilatates, whereby the generated pressure is-actingon the tested metallic bar or another substance 6 the volume of whichbegins to decrease: The generated heat is absorbed by the body l Afterthe cooling of the tested bar 6 the closing t'is opened, then thecurrent is switched on'once more so that by another dilatation of thebar 5 the tested bar 6 is pressed out of the cavity of the body I,whereafter the compressed material may be used for various purposes.

The' pressure acting on the bar 6 may eventually increase its hardnessand change its crystallic structure. The material obtained in this waymay be used e. g. as welded cutting-edge of working machines whereby theexpensive'agglomerate tools could be replaced.

It has been found that the same principle" may be used to generate highpressures. in a similar device if the whole device is heated. For thispurpose a small dilatation bar is used, made of a material having adilatation coefiicient substantially different from that of theothermaterial of which the device is made, e. g. steel. If thedilatation bar, used for theexperiment', is

made of a material having a higher dilatation coefficient than that ofthe other material of which the device is made, e. g. a zinc dilatationbar, closed in a steel cylinder, a high pressure is generated alreadywhen the whole device is heated to a certain temperature, e. g. 300 C.If on the contrary, a dilatation bar, made of a material, the dilatationcoeflicient of which is lower, e. g. of Invar, is used and the device,the body of which is made e. g. of steel, a high pressure is producedduring the cooling only, supposing of course, that the Invar bar hasbeen put into a preheated steel body and still in warm state tightenedtherein.

The method according to the invention offers the advantage that there isnot necessary to use an insulating internal jacket and that the heatingcan be carried out in any way, e. g. by means of a direct flame fromoutside or by means of an induced current.

Example I A substance which shall be subjected to the action of pressureand a zinc bar, tightly fitting inside of the body after the tighteningof the screw closing, are lodged into a steel cylinder with a deep boreof a small inner width and provided by a screw closing. The otherarrangement of the device is identical with the Fig. l, with theexception that there is no warm insulating inside cylindric jacketwhereas at the left hand neither a special cover nor a projection and acurrent line are necessary. On this end the body I is simply closed. Theclosed device is then slowly heated to a temperature of 300 C. A zincbar having a thermic dilation coefiicient 2-2 /2 times larger than thatof steel, 2. high pressure is generated inside of the zinc bar andsimultaneously inside of the tested substance.

Example II The same device is preheated to a temperature of 300-400 C.then a closely fitting Invar bar is lodged therein, the closing beingscrewed in and duly tightened. Thereafter the whole device is let tocool slowly. During the cooling the steel block is contracting 7 timesmore than the Invar bar so that a high pressure of several tens ofthousands of atmospheres is generated.

The Fig. 2 shows a section of the right hand end of the device for theproduction of very high pressures. In such cases the hollow cylinder 2is subjected to very high pressures and therefore is to be made of aninsulation material of a high resistance to pressure and of a smallcoefficient of thermic dilatability. Silicate glass or melted corundumare suitable for this purpose. The cylinder 2 is placed in the jacketbody I in warm state and is secured therein on one extremity by aclosing stopper 8 provided with a thread cooperating with a threadedportion of the body I. The stopper 8 can be rotated by inserting asuitable tool into the bore 23 on the front side of the stopper. Thepoints 3a, 4a of the closing cones 3, 4, which are in a close contactwith the bar 5 or with the material 6 respectively are made of a hardmetal. The closing cone 3 on the left hand side of the device has adiameter by about 25% larger than that of the right hand closing cone 4in order to secure a sufiicient supply of electric current by means ofthe electrode I3. Both cones are made of high speed tool steelcontaining about 4% chromium, 1% vanadium and 18% tungsten. In order toenable the cones 3, 4 to be duly pressed against the 4 material,subjected to pressure, the bolts of the tightening screws 24 are in thepart passing by bushings or jackets I9 provided by spiral channels I8,the ends of which are through bores I5, I6 conducted up to the surfaceof the screw heads 24. The jackets I9 are lodged in warm state into theclosing 8.

Before bringing the device into action a heating medium is conductedinto channels I6, I8, I5, this mediums heating thoroughly the closingcones 3, 4, which are expanding and thereby pressing against the otheradjacent material. If it is necessary to take out the closing cones, acold medium is driven through the channels, whereby the cones arecooled, reduced in volume and loosened.

In order to prevent a deformation of the conic inside-wall of the hollowcylinder 2 owing to an overpressure after a screwing out of one or thecones out of the device, it is necessary to reduce the radialoverpressure before such a screwing out. For this purpose the annulus 2I, embracing the bush I, forms simultaneously a covering wall of thechannels 20, cut in the form of a thread in the surface of the body Ionto which the annulus 2I is fitted in warm state. The mouths of thechannel 20 are arranged on the surface of the annulus 2I both on theright and on the left in the bores 22. If the overpressure acting at allsides onto the hollow cylinder 2, is to be reduced, a hot medium isdriven through the channels 22, 20 this medium imparting the heat to thebody I, by expansion of which the overpressure acting onto the cylinder2 is reduced. On the contrary, before putting the device into action, acold medium is led through these channels, producing a volume reductionof the body I which thus becomes tightly fitting to the cylinder 2.

The annulus 2|, jackets or bush insert pieces I9, stopper 8, conicinsert pieces 9 and the body I are made of special steel. The tubes llof the channels I6 are made of asbestos, the tubes I4 of the electriclines I3, I3 of fibre, the insulating washers and underlayers I0, II, I2of silicate glass, the cones 3a, 4a and 9a of a hard metal. The hollowconic insert piece 917 is made of melted corundum.

The functioning of the arrangement corresponds to that of the apparatusaccording to the Fig. 1.

A tightly filling up of the inside bore of the cylinder by the bar 5 maybe carried out mechanically or electrolytically.

According to the necessity and purpose the electric current may beconducted only into the dilatating bar 5 from the left hand electrode I3and the tightening cone 3, 3a, and furthermore through the cones 9a, 9into the close 8, or it is possible to heat by means of the currentevent the compressed substance 6 in such a way that the current is notconducted from the right hand extremity of the bar 5 into the parts 9a,9 and 8, but through the mass 6 into the cone 4a, 4 and through theright hand electrode I3 away or, of course, in the opposed direction.

The copper electric lines i3 and I3 must have a sufficiently largecontact surface with their closing cones 3 and 4 and a sufficientlylarge diameter in order not to get warm too much, the amount of currentpassing through them being considerably large as it is necessary tocompensate the current losses due to the leading away of heat by thehollow cylinder 2 from the dilatating bar 5 and by the insulating conicinsertion 9b from the tested mass 6, when they are heated 'to hightemperatures.

The left hand part of the device is quite analog-i0 with the exceptionof the mass 6, subjected to pressure, which of course, is dispensedwith, so that the cone 3 touches by its top piece 3a the left handextremity of the dilatating bar -'5. The parts 9a, -9 and -$b areequally dispensed with.

1. A device for exerting a pressure on a body, comprising incombination, a body provided with a hollow; means for tightly closingthe hollow of said body; a metal bar and a body to be compressedarranged in the hollow of said body abutting against each other andopposite walls of said hollow; and means for imparting temperaturechanges to said bar.

2. A device for exerting a pressure on a body, comprising incombination, a body provided with a hollow; means for tightly closingthe hollow of said body; a metal bar and a body to be compressedarranged in the hollow of said body abutting against each other andopposite walls of said hollow; and means for causing temperature changesbetween said bar and said hollow body.

3. A device for exerting a pressure on a body, comprising incombination, a body provided with an elongated hollow; means for tightlyclosing the hollow of said body; a metal bar and a body to be compressedarranged in the hollow of said body abutting against each other andopposite walls of said hollow and filling the hollow of said bodytightly; and means for imparting temperature changes to said bar.

4. A device for exerting a pressure on a body comprising in combination,a body provided with an elongated hollow; means for tightly closing thehollow of said body; a metal bar and a body to be compressed arranged inthe hollow of said body abutting against each other and opposite wallsof said hollow and filling the hollow of said body tightly; and meansfor causing temperature changes between said bar and said hollow body.

5. A device for exerting a pressure on a body, comprising incombination, a body provided with an elongated hollow; means for tightlyclosing the hollow of said body; a metal bar and a body to be compressedarranged in the hollow of said body abutting against each other andopposite walls of said hollow and filling the hollow of said bodytightly; and means for electrically heating said bar.

6. A device for exerting a pressure on a body,

comprising in combination, a body provided with l an elongated hollow;means for tightly closing the hollow of said body; a metal bar and abody to be compressed arranged in the hollow of said body abuttingagainst each other and opposite walls of said hollow and filling thehollow of said body tightly; means for insulating electrically said barfrom said hollow body; and means for leading an electric current throughsaid bar.

'7. A device for exerting a pressure on a body, comprising incombination, a body provided with a hollow; means for tightly closingthe hollow of said body; a tube made of thermically and electricallyinsulating material and arranged in the hollow of said body; a metal barand a body to be compressed tightly arranged in said tube abuttingagainst each other and opposite walls of said tube; and means forleading an electric current through said bar and said body to becompressed.

8. A device for exerting a pressure on a body, comprising in combinationa body provided with ahollow; means for tightly closing the hollow ofsaid body; a tube made of thermicallyand electrically insulatingmaterial having a low coefiicient of thermal expansion and arranged inthe-hollow of said body; a metal bar and a body to be compressed tightlyarranged in said tube abutting against each other and opposite walls ofsaid tube, and means for leading an electric current through said barand said body to be compressed.

9. A device for exerting a pressure on a body comprising in combination,a body provided with a hollow; means for tightly closing the hollow ofsaid body; :a metal bar and a body to becompressed arranged in thehollow of said body abutting against each other and opposite walls ofsaid tube; said bar having a lower coefiicient of thermal expansion thansaid hollow body.

1 0. A device for exerting a high pressureon a body comprising incombination, a body provided with an elongated hollow; means for tightlyclosing the hollow of said body; said means including conical closurepieces arranged at opposite ends of the hollow of said body; a metal 1bar and a body to be compressed arranged in the hollow of said bodyabutting against each other, and against said conical closure pieces;and means for leading an electric current through said bar and said bodyto be compressed.

11. A device for exerting a high pressure on a body comprising incombination, a body provided with an elongated hollow; means for tightlyclosing the hollow of said body, said means including a conical insertpiece provided with an axial bore; a metal bar arranged in the hollow ofsaid body; a body to be compressed arranged in the bore of said conicalinsert piece, said metal bar and said body to be compressed abuttingagainst each other and opposite walls of said hollow; and means forleading an electric current through said bar and said body to becompressed.

12. A device for exerting a high pressure on a body comprising incombination, a body provided with an elongated hollow; means for tightlyclosing the hollow of said body, said means including a conical insertpiece provided with an axial bore; a metal bar arranged in the hollow ofsaid body and having a lower coefficient of thermal expansion than saidhollow body; a body to be compressed arranged in the bore of saidconical insert piece, said metal bar and said body to be compressedabutting against each other and opposite walls of said hollow; and meansfor leading an electric current through said bar and said body to becompressed.

13. A device for exerting a high pressure on a body comprising incombination, a steel body provided with an elongated hollow; means fortightly closing the hollow of said body, said means including a conicalinsert piece made from molten corundum provided with an axial bore; ametal bar arranged in the hollow of said body; a body to be compressedarranged in the bore of said conical insert piece, said metal bar andsaid body to be compressed abutting against each other and oppositewalls of said hollow; and means for leading an electric current throughsaid bar and said body to be compressed.

14. A device for exerting a high pressure on a body comprising incombination a body-provided with an elongated hollow; means for tightlyclosing the hollow of said body, said means including a conical insertpiece provided with an axial bore; a metal bar arranged in the hollow ofsaid body; a body to be compressed arranged in the bore of said conicalinsert piece, said metal bar and said body to be compressed abuttingagainst each other and opposite walls of said hollow; a coneconcentrically arranged in said insert piece and being in close contactwith said body to be compressed; and means for leading an electriccurrent through said bar and said body to be compressed; said leadingmeans including a conductor arranged in said cone.

J OSEF MORAVEC.

REFERENCES CITED UNITED STATES PATENTS Name Date Williamson May 24, 1892Number Number Number 8 Name Date Weintraub et al. Aug. 26, 1913Goldschmidt et al. Nov. 20, 1917 Brown et a1 July 11, 1922 Fritsche Nov.10, 1925 Williams June 24, 1930 Paugh Dec. 9, 1930 Taylor Feb. 7, 1933Spencer Dec. 12, 1933 Bates Oct. 17, 1939 Renner Feb. 11, 1941 BarnesMar. 26, 1946 Mackay May 13, 1947 FOREIGN PATENTS Country Date GermanyOct. 1, 1913

